dpy-18 encodes an alpha-subunit of prolyl-4-hydroxylase in Caenorhabditis elegans

Collagen is an extracellular matrix (ECM) component encoded by a large mult igene family in multicellular animals. Procollagen is post-translationally modified by prolyl-4-hydroxylase (EC 1.14.11.2) before secretion and partic ipation in ECM formation. Therefore, collagen processing and regulation can be studied by examining this required interaction of prolyl-4-hydroxylase with procollagen. High-resolution polymorphism mapping was used to place th e Caenorhabditis elegans dpy-18 gene on the physical map, and we show that it encodes a prolyl-4-hydroxylase alpha catalytic subunit. The Dpy phenotyp e of dpy-18(e364) amber mutants is more severe when this mutation is in tra ns to the noncomplementing deficiency tDf7, while the dpy-18(e499) deletion mutant exhibits the same phenotype as dpy-18(e499)/tDf7 Furthermore, dpy-1 8 RNA. interference (RNAi) in wild-type worms results in Dpy progeny, while dpy-18 (RNAi) in dpy-18(e499) mutants does not alter the Dpy phenotype of their progeny. These observations suggest that the dpg-18 null phenotype is Dpy. A dpy-18::gfp promoter fusion construct is expressed throughout the h ypodermis within the cells that abundantly produce the cuticle collagens, a s well as in certain head and posterior neurons. While prolyl-4-hydroxylase has been studied extensively by biochemical techniques, this is the first report of a mutationally defined prolyl-4-hydroxylase in any animal.